Departments of Plant Pathology and Entomology, University of California, Davis, CA 95616, USA.
Proc Natl Acad Sci U S A. 2011 Jun 7;108(23):9350-5. doi: 10.1073/pnas.1100773108. Epub 2011 May 23.
Vector infection by some animal-infecting parasites results in altered feeding that enhances transmission. Modification of vector behavior is of broad adaptive significance, as parasite fitness relies on passage to a new host, and vector feeding is nearly always essential for transmission. Although several plant viruses infect their insect vectors, we have shown that vector infection by a plant virus alters feeding behavior. Here we show that infection with Tomato spotted wilt virus (TSWV), type member of the only plant-infecting genus in the Bunyaviridae, alters the feeding behavior of its thrips vector, Frankliniella occidentalis (Pergande). Male thrips infected with TSWV fed more than uninfected males, with the frequency of all feeding behaviors increasing by up to threefold, thus increasing the probability of virus inoculation. Importantly, infected males made almost three times more noningestion probes (probes in which they salivate, but leave cells largely undamaged) compared with uninfected males. A functional cell is requisite for TSWV infection and cell-to-cell movement; thus, this behavior is most likely to establish virus infection. Some animal-infecting members of the Bunyaviridae (La Crosse virus and Rift Valley fever virus) also cause increased biting rates in infected vectors. Concomitantly, these data support the hypothesis that capacity to modify vector feeding behavior is a conserved trait among plant- and animal-infecting members of the Bunyaviridae that evolved as a mechanism to enhance virus transmission. Our results underscore the evolutionary importance of vector behavioral modification to diverse parasites with host ranges spanning both plant and animal kingdoms.
某些感染动物的寄生虫的载体感染会导致改变摄食行为，从而增强传播。载体行为的改变具有广泛的适应性意义，因为寄生虫的适应性依赖于传播到新的宿主，而载体的摄食几乎总是传播所必需的。尽管有几种植物病毒感染其昆虫载体，但我们已经表明，植物病毒对载体的感染会改变其取食行为。在这里，我们表明感染番茄斑萎病毒（TSWV），即 Bunyaviridae 家族中唯一感染植物的病毒，会改变其烟粉虱（Frankliniella occidentalis）的取食行为。感染 TSWV 的雄性烟粉虱比未感染的雄性烟粉虱取食更多，所有取食行为的频率增加了多达三倍，从而增加了病毒接种的可能性。重要的是，感染的雄性烟粉虱进行的非摄食探测（在探测过程中它们会分泌唾液，但基本不会破坏细胞）几乎比未感染的雄性烟粉虱多三倍。功能细胞是 TSWV 感染和细胞间运动所必需的；因此，这种行为最有可能建立病毒感染。Bunyaviridae 家族中的一些感染动物的成员（拉科罗病毒和裂谷热病毒）也会导致感染载体的叮咬率增加。同时，这些数据支持这样的假设，即改变载体取食行为的能力是 Bunyaviridae 家族中感染植物和动物的成员的一个保守特征，这是作为增强病毒传播的一种机制而进化而来的。我们的研究结果强调了载体行为改变对宿主范围跨越植物和动物王国的各种寄生虫的进化重要性。
